a = "A".ord
z = "Z".ord
diff = z - a
gets.chomp.chars.each_with_index do |s, i|
    x = (i + 1) % (diff + 1)
    ord = s.ord
    index = ord - x
    if index < a
        index = 1 + z - x + (ord - a)
    end
    print index.chr
end
puts